LaMgAl11O19∶Eun+ (n=2,3) was synthesized by solid state reaction using H3BO3 as a flux at 1 400 ℃ for 4 hours. And their luminescent properties was investigated under UV and VUV excitation. Strong pure blue emission...LaMgAl11O19∶Eun+ (n=2,3) was synthesized by solid state reaction using H3BO3 as a flux at 1 400 ℃ for 4 hours. And their luminescent properties was investigated under UV and VUV excitation. Strong pure blue emission due to d-f transition of Eu2+ was observed in LaMgAl11O19∶Eu2+ both in 254 nm and 147 nm excitation. At the same time, red emission due to 5D0 → 7FJ (J=0, 1, 2, 3, 4) transition of Eu3+ also observed in LaMgAl11O19∶Eu3+. The dependence of emission intensity of blue/red emission on Eu2+ / Eu3+-content was evaluated. The result indicated that the blue emission intensity was arrived optimum when Eu2+-content was 0.10 mol·mol-1 under both UV and VUV excitation while red emission intensity reached optimum when Eu3+-content was 0.125 mol·mol-1 under UV excitation. This suggests that LaMgAl11O19∶Eu2+ phosphors could be potential blue phosphor for the application in PDP.展开更多
利用复杂晶体化学键的平均能带模型研究了LaMAl11O19(M =Mg ,Fe)晶体的化学键性质。结果表明 ,La O键只有 3%的共价性 ,4f1格位却具有很强的共价特征。晶体中各格位共价次序为 :La O <Al(5) O <Al(1) O <Al(4 ) O <Al(2 ...利用复杂晶体化学键的平均能带模型研究了LaMAl11O19(M =Mg ,Fe)晶体的化学键性质。结果表明 ,La O键只有 3%的共价性 ,4f1格位却具有很强的共价特征。晶体中各格位共价次序为 :La O <Al(5) O <Al(1) O <Al(4 ) O <Al(2 ) O <Al(3) O <M O。其中 2d格位和 4e格位具有强的各向异性特征。利用由共价性和极化率定义的化学环境因子h计算了LaFeAl11O19中57Fe的穆斯堡尔同质异能位移和LaMgAl11O19∶Eu中151Eu的同质异能位移 。展开更多
本文通过晶格取代作用 ,制备了以 Ni为活性组分的六铝酸盐复合氧化物催化剂 Sr Ni Al11O19-δ,并通过XRD,XPS,TPR等实验技术 ,对催化剂的结构和性质进行了表征。结果表明 ,六铝酸盐 Sr Ni Al11O19-δ对二氧化碳重整甲烷制合成气反应具...本文通过晶格取代作用 ,制备了以 Ni为活性组分的六铝酸盐复合氧化物催化剂 Sr Ni Al11O19-δ,并通过XRD,XPS,TPR等实验技术 ,对催化剂的结构和性质进行了表征。结果表明 ,六铝酸盐 Sr Ni Al11O19-δ对二氧化碳重整甲烷制合成气反应具有良好的催化活性和稳定性 ,在 780℃反应 2小时 ,CH4 和 CO2 转化率分别为 95 .0 %和 93 .4% ,没有发现活性组分 Ni高温烧结和催化剂失活。展开更多
文摘LaMgAl11O19∶Eun+ (n=2,3) was synthesized by solid state reaction using H3BO3 as a flux at 1 400 ℃ for 4 hours. And their luminescent properties was investigated under UV and VUV excitation. Strong pure blue emission due to d-f transition of Eu2+ was observed in LaMgAl11O19∶Eu2+ both in 254 nm and 147 nm excitation. At the same time, red emission due to 5D0 → 7FJ (J=0, 1, 2, 3, 4) transition of Eu3+ also observed in LaMgAl11O19∶Eu3+. The dependence of emission intensity of blue/red emission on Eu2+ / Eu3+-content was evaluated. The result indicated that the blue emission intensity was arrived optimum when Eu2+-content was 0.10 mol·mol-1 under both UV and VUV excitation while red emission intensity reached optimum when Eu3+-content was 0.125 mol·mol-1 under UV excitation. This suggests that LaMgAl11O19∶Eu2+ phosphors could be potential blue phosphor for the application in PDP.
文摘利用复杂晶体化学键的平均能带模型研究了LaMAl11O19(M =Mg ,Fe)晶体的化学键性质。结果表明 ,La O键只有 3%的共价性 ,4f1格位却具有很强的共价特征。晶体中各格位共价次序为 :La O <Al(5) O <Al(1) O <Al(4 ) O <Al(2 ) O <Al(3) O <M O。其中 2d格位和 4e格位具有强的各向异性特征。利用由共价性和极化率定义的化学环境因子h计算了LaFeAl11O19中57Fe的穆斯堡尔同质异能位移和LaMgAl11O19∶Eu中151Eu的同质异能位移 。
文摘本文通过晶格取代作用 ,制备了以 Ni为活性组分的六铝酸盐复合氧化物催化剂 Sr Ni Al11O19-δ,并通过XRD,XPS,TPR等实验技术 ,对催化剂的结构和性质进行了表征。结果表明 ,六铝酸盐 Sr Ni Al11O19-δ对二氧化碳重整甲烷制合成气反应具有良好的催化活性和稳定性 ,在 780℃反应 2小时 ,CH4 和 CO2 转化率分别为 95 .0 %和 93 .4% ,没有发现活性组分 Ni高温烧结和催化剂失活。
